This disclosure generally relates to air or other gas treatment, and specifically to catalytic ozone removal.
Ozone is a well-known terrestrial air pollutant, and is also a naturally occurring component of the Earth's atmosphere. Ozone levels in the Earth's atmosphere are known to vary with altitude and seasonally, and aircraft with pressurized cabins that rely on compressed outside air for replenishment of cabin air can experience undesirably high ozone levels in the cabin or other pressurized areas. Ozone concentrations at typical flight cruising altitudes can be significantly higher than the 0.25 ppmv limit set by the FAA for aircraft cabin air. Accordingly, aircraft environmental conditioning systems (ECS) are commonly equipped with equipment for removing ozone from the air.
One technique to remove ozone is to catalytically decompose the ozone molecules to form oxygen molecules according to the reaction represented by the formula:2O3→3O2 Catalytic decomposition of ozone can be effective, but the effectiveness can decrease over time. In some cases, the effectiveness of the catalyst can decrease to a level where the catalyst must be replaced. Various technologies have been proposed for catalytic ozone decomposition, such as optimizing the formulation of the catalyst composition; however, there continues to be a demand for new approaches for ozone removal.